In a high-frequency module having a semiconductor chip and an antenna mounted on a substrate, for example, influences of loss and reflection due to impedance mismatch in a solder joint part and loss in a transmission line are increased in an attempt to transmit a high-frequency signal such as millimeter waves and terahertz waves, for example.
This is because, since the wavelength is reduced in a high-frequency region such as millimeter waves and terahertz waves, for example, the influences of the loss and reflection in the solder joint part and the loss in the transmission line on the transmitted signals are increased even for the solder joint part or a short transmission line.
As a result, signal quality between the semiconductor chip and the antenna is reduced, leading to reduction in performance of the high-frequency module. Also, the influence on high-frequency characteristics is also increased by variations during mounting. Therefore, it is conceivable to use a heterogeneous device integration technology such as Fan-Out Wafer Level Packaging (FO-WLP) and a pseudo System onChip (SoC) technology, for example, to realize high manufacturing stability by connecting the semiconductor chip and the antenna with low loss by a wide short transmission line and thus reducing the module in size, without using the solder joint part to connect the semiconductor chip and the antenna.
Note that the heterogeneous device integration technology is a technology to manufacture a module having heterogeneous devices integrated therein by disposing devices (elements) close to each other, sealing the devices with a resin to form a pseudo-wafer, connecting the devices to each other through rewiring lines using a rewiring technology and dicing the wafer into pieces having a chip size. This technology may reduce the size of the module since the devices may be disposed close to each other. Also, the loss may be reduced since the devices may be connected to each other at a short distance. Moreover, the devices may be connected to each other without using solder joint. The devices may be connected to each other with low loss since the transmission line (signal line) may be increased in width compared with a semiconductor process. Furthermore, high manufacturing stability may be realized while reducing manufacturing variations.
Related techniques are disclosed in, for example, Japanese Laid-open Patent Publication Nos. 2007-235199, 2005-167966, 2002-314323, and 2002-76237, and Japanese Unexamined Utility Model Registration Application Publication No. 63-95306.
Related techniques are also disclosed in, for example, Mahmoud Al Henawy et al., “Integrated Antennas in eWLB Packages for 77 GHz and 79 GHz Automotive Radar Sensors”, Proceedings of the 8th European Radar Conference, 12-14 Oct. 2011, UK.